Checking out the videos from Musikmesse I came across the pretty awesome looking Korg Monotron. I decided to knock up a quick version as I am currently working on MS-20 style filters and thought this would be a nice test platform.

I had to guess pretty much how it works as I don’t have much to go on, not even the vco shape (sounds like a saw to me). Obviously won’t sound nearly as good as the real thing but might give some idea of the kinds of sounds it could produce.

Click to play:


I was totally amazed today to get an email from none-other than the designer of the Monotron himself. He congratulated me on the implementation and gave me a few hints:

– filter doesn’t sound nearly as aggressive at maximum peak.
– LFO is slower at minimum (about 15s period) and faster at maximum (>1kHz).
– monotron resets the LFO at the moment the ribbon is touched, so it
works like a simple cycling EG at slow LFO rates.
– monotron has fixed intensity keytrack. cutoff tracks ribbon position
by factor of two. only tracks ribbon not pitch knob.

I made the adjustments above and also added keyboard control for the ribbon.

It doesn’t sound particularly good at extreme modulation, something that is very hard to do digitally and where analogs really shine. I’ll have to come back to this one when I get my hands on a real Monotron and try getting a bit closer to that beautiful analog squelching.

Special thanks to Tatsuya Takahashi and Korg, can’t wait for the real thing!

11 Responses to “Webotron”

  1. mothy Says:


  2. ugo capeto Says:

    Could you possibly briefly explain how you write such a program ? It’s all java ? Similar to flash ?

  3. admin Says:

    Briefly – not really it’s fairly involved. But yes it’s all Java and quite different to code than flash. Flash is much less capable of real-time audio (but it’s getting there). If you want to learn this sort of thing you will need to read a book or two on Java and Audio DSP. The maths behind generating sound properly is not trivial and has taken me several years to get to grips with. I have also been programming for 10 years.

  4. ugo capeto Says:

    thanks for the answer. tbh, i’d be content with creating any blip at the correct standard pitches (C4, etc). not too worried about aound synthesis per se. i’ve also been programming for a long time, just not in java or flash.

  5. jay Says:

    Hi for me there is a strange cycling kind of pitched tone on both WS-101 and this. It cant be intentional. just to let you know

  6. admin Says:

    How pronounced is the cyclic sound and what sort of frequency is it? Is it dependent on pitch or anything else? Thanks for the feedback.

  7. jay Says:

    updating to latest java for mac ( seemed to solve it.

  8. steve g Says:

    you have some great virtual synths, any prospect of them becoming ported as VST instruments?

  9. admin Says:

    I don’t really have much incentive to port to VST. I’m not very talented musically and I don’t own any vst hosts. I doubt I could sell any of them as there are better sounding free instruments out there already. If I come up with something unique that sounds great I might consider it.

  10. Cody Says:

    First site I went to on the iPad. Won’t work, though it is java….

  11. Cynosure Says:

    Can you make a version of this for Android? Apparently Android uses an open source version of java that is very similar. It might be as simple as changing the .class filenames to .dex

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